Earnings Per Share (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Earnings Per Share, Basic and Diluted [Abstract]
Shareholders' net income	$ 505	$ 380	$ 562	$ 751
Shares (in thousands):
Weighted average	282,043,000	285,690,000	282,919,000	285,425,000
Common stock equivalents	5,043,000	4,857,000	5,248,000	4,348,000
Total shares	287,086,000	290,547,000	288,167,000	289,773,000
Shareholders' net income per share basic	$ 1.79	$ 1.33	$ 1.99	$ 2.63
Shareholders net income per share effect of dilution	$ (0.03)	$ (0.02)	$ (0.04)	$ (0.04)
Shareholders' net income per share diluted	$ 1.76	$ 1.31	$ 1.95	$ 2.59
Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract]
Antidilutive options	1,800,000	2,400,000	1,800,000	3,100,000
Common shares held in Treasury	82,496,367	77,780,090	82,496,367	77,780,090